* [PATCH] gdb/nat/linux-osdata.c: fix build on gcc-12 (string overfow)
@ 2021-11-14 17:32 Sergei Trofimovich
2021-11-15 0:30 ` Simon Marchi
0 siblings, 1 reply; 3+ messages in thread
From: Sergei Trofimovich @ 2021-11-14 17:32 UTC (permalink / raw)
To: binutils; +Cc: gdb-patches, Sergei Trofimovich
From: Sergei Trofimovich <siarheit@google.com>
On gcc-12 build fails as:
gdbserver/../gdb/nat/linux-osdata.c: In function 'void linux_xfer_osdata_processes(buffer*)':
gdbserver/../gdb/nat/linux-osdata.c:330:39: error:
'__builtin___sprintf_chk' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
330 | sprintf (core_str, "%d", i);
| ^
It's an off-by-one case in an unlinely scenario for negative
huge core count. The change assumes smalles negative value to
include sign.
---
gdb/nat/linux-osdata.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index 9746d1210fe..18b6f40cb78 100644
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -320,12 +320,12 @@ linux_xfer_osdata_processes (struct buffer *buffer)
/* Find CPU cores used by the process. */
cores = XCNEWVEC (int, num_cores);
task_count = get_cores_used_by_process (pid, cores, num_cores);
- cores_str = (char *) xcalloc (task_count, sizeof ("4294967295") + 1);
+ cores_str = (char *) xcalloc (task_count, sizeof ("-2147483648") + 1);
for (i = 0; i < num_cores && task_count > 0; ++i)
if (cores[i])
{
- char core_str[sizeof ("4294967295")];
+ char core_str[sizeof ("-2147483648")];
sprintf (core_str, "%d", i);
strcat (cores_str, core_str);
--
2.33.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] gdb/nat/linux-osdata.c: fix build on gcc-12 (string overfow)
2021-11-14 17:32 [PATCH] gdb/nat/linux-osdata.c: fix build on gcc-12 (string overfow) Sergei Trofimovich
@ 2021-11-15 0:30 ` Simon Marchi
2021-11-15 10:54 ` Pedro Alves
0 siblings, 1 reply; 3+ messages in thread
From: Simon Marchi @ 2021-11-15 0:30 UTC (permalink / raw)
To: Sergei Trofimovich, binutils; +Cc: Sergei Trofimovich, gdb-patches
On 2021-11-14 12:32, Sergei Trofimovich via Gdb-patches wrote:
> From: Sergei Trofimovich <siarheit@google.com>
>
> On gcc-12 build fails as:
>
> gdbserver/../gdb/nat/linux-osdata.c: In function 'void linux_xfer_osdata_processes(buffer*)':
> gdbserver/../gdb/nat/linux-osdata.c:330:39: error:
> '__builtin___sprintf_chk' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
> 330 | sprintf (core_str, "%d", i);
> | ^
>
> It's an off-by-one case in an unlinely scenario for negative
> huge core count. The change assumes smalles negative value to
> include sign.
> ---
> gdb/nat/linux-osdata.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
> index 9746d1210fe..18b6f40cb78 100644
> --- a/gdb/nat/linux-osdata.c
> +++ b/gdb/nat/linux-osdata.c
> @@ -320,12 +320,12 @@ linux_xfer_osdata_processes (struct buffer *buffer)
> /* Find CPU cores used by the process. */
> cores = XCNEWVEC (int, num_cores);
> task_count = get_cores_used_by_process (pid, cores, num_cores);
> - cores_str = (char *) xcalloc (task_count, sizeof ("4294967295") + 1);
> + cores_str = (char *) xcalloc (task_count, sizeof ("-2147483648") + 1);
>
> for (i = 0; i < num_cores && task_count > 0; ++i)
> if (cores[i])
> {
> - char core_str[sizeof ("4294967295")];
> + char core_str[sizeof ("-2147483648")];
>
> sprintf (core_str, "%d", i);
> strcat (cores_str, core_str);
>
The problem could also be avoided by using %u and making i unsigned.
But actually, would you mind updating this code so that cores_str is an
std::string and you just append to it? That would get rid of the manual
memory management. I'm expecting that it could just look like this (but
I haven't tested):
std::string cores_str;
for (i = 0; i < num_cores && task_count > 0; ++i)
if (cores[i])
{
cores_str += string_printf ("%d", i);
task_count -= cores[i];
if (task_count > 0)
cores_str += ',';
}
Simon
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] gdb/nat/linux-osdata.c: fix build on gcc-12 (string overfow)
2021-11-15 0:30 ` Simon Marchi
@ 2021-11-15 10:54 ` Pedro Alves
0 siblings, 0 replies; 3+ messages in thread
From: Pedro Alves @ 2021-11-15 10:54 UTC (permalink / raw)
To: Simon Marchi, Sergei Trofimovich, binutils
Cc: gdb-patches, Sergei Trofimovich
On 2021-11-15 00:30, Simon Marchi via Binutils wrote:
> But actually, would you mind updating this code so that cores_str is an
> std::string and you just append to it? That would get rid of the manual
> memory management. I'm expecting that it could just look like this (but
> I haven't tested):
>
> std::string cores_str;
> for (i = 0; i < num_cores && task_count > 0; ++i)
> if (cores[i])
> {
> cores_str += string_printf ("%d", i);
You can use string_appendf instead to save allocating/destroying a new string:
string_printf (cores_str, "%d", i);
Pedro Alves
>
> task_count -= cores[i];
> if (task_count > 0)
> cores_str += ',';
> }
>
> Simon
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-11-15 10:54 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-14 17:32 [PATCH] gdb/nat/linux-osdata.c: fix build on gcc-12 (string overfow) Sergei Trofimovich
2021-11-15 0:30 ` Simon Marchi
2021-11-15 10:54 ` Pedro Alves
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).